1. Field of the Invention
The present disclosure relates to multi-pass heat exchangers. More particularly, the present disclosure relates to a multi-pass heat exchanger having a distributing insert in the return manifold.
2. Description of Prior Art
Refrigeration systems are well known in the art and ubiquitous in such industries as food service, chemical, residential and commercial cooling, and automotive. On a larger scale, heat exchangers are required for office buildings and for residential purposes. Lack of efficiency is a great concern with such systems.
Traditional refrigeration cycles, or air conditioners, include a compressor, a condenser, an expansion valve, an evaporator, and a refrigerant whose evaporation creates the cool temperature. In some refrigeration systems, the evaporator is a series of parallel narrow tubes, which provide parallel refrigerant paths. When the refrigerant passes through the expansion valve, a pressure and temperature drop occurs.
In many refrigerant vapor compression systems, as the refrigerant passes through the expansion valve, a portion of the fluid expands to vapor. The resulting two-phase mixture can cause maldistribution in the evaporator, which is a common problem with heat exchangers that use parallel refrigerant paths, resulting in poor heat exchanger efficiency. For heat exchangers that have relatively few parallel refrigerant paths (typically 20 or less), even distribution of the two-phase fluid is achieved through a distribution device that individually feeds each parallel refrigerant path. However, for heat exchanges with many parallel refrigerant paths (typically more than 20), individual distribution to each parallel refrigerant path is often not practical. In most cases, a simple inlet header is used, which can lead to significant refrigerant maldistribution to the heat exchanger. Additionally, gravity and the increase in overall volume as the flow transitions from the expansion device to the inlet header also act to cause the liquid and vapor to separate.
Previously, it has been proposed by U.S. Pat. No. 7,143,605 to include a distributor tube positioned within the inlet manifold to reduce maldistribution. While the distributor tube within the inlet manifold has proven to be helpful to reduce maldistribution, the maldistribution of the liquid-phase and vapor-phase within the heat exchanger remains problematic.
Therefore, there exists a need for heat exchanger that overcome, alleviate, and/or mitigate one or more of the aforementioned and other deleterious effects of prior art heat exchangers.